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University of Copenhagen
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Danish scientist gets huge five-year EU grant to understand quantum physics phenomenon

People — Søren Fournais is one of the world's leading researchers into quantum mechanical equations. Now he has to solve mysteries that no-one has ever been able to solve before.

Who is he?

Søren Fournais (49) is Professor at the Department of Mathematical Sciences and the Centre for the Mathematics of Quantum Theory at the University of Copenhagen. The centre is a world leader in the mathematical understanding of quantum physics, and the work consists partly in finding proofs for already known equations.

»A typical week begins with you having some new good ideas from the weekend that you would like to pursue, and then you work hard on Monday, Tuesday and Wednesday. Then it looks like it works, but by Thursday we find out that it does not work anyway. But then you’ve learned more about it, and then the next round of ideas for the week ahead is perhaps a little bit more validated. And at some point, everything falls into place,« Søren Fournais says in a press release from the University of Copenhagen.

He got his PhD From Aarhus University at the age of 26, after which he worked as a postdoc at the Erwin Schrödinger Institute in Vienna and at Université de Paris-Sud, before returning to Aarhus as associate professor and later as professor in 2006. In 2014, he became a member of the Royal Danish Academy of Sciences and Letters, and in 2022 was hired by UCPH.

Over the past ten years, Søren Fournais has investigated the weird characteristics of the so-called Bose-Einstein-condensates – a quantum state where millions of atoms condense and move in concert. This has a certain beauty, according to him, and this is also the reason why you are reading about him now.

Why am I reading about him now?

With a grant of DKK 15 million from the European Research Council, Søren Fournais will dedicate the next five years to solving the equations of the mystical quantum phenomenon of the Bose-Einstein-condensates:

»Imagine one of those spectacular opening ceremonies at the Olympic Games, where a huge crowd of people suddenly coerce as a unit, making the same movements synchronously like a flock of starlings. This also happens in the world of atoms under some very particular and extraordinary conditions. Here it is a million atoms, all of which enter into the same quantum state and in this way behave in a completely synchronous manner,« explains Søren Fournais.

When the atoms are cooled to close to absolute zero, the lowest possible temperature of -273,15 °C, they enter a fifth phase that is neither liquid, solid, gas or plasma.

»My big dream is to mathematically prove the Bose-Einstein-condensation phase transition. But showing the phase transition is extremely difficult, because we take for granted that the particles are moving randomly until the point they stick together. It is very difficult to see why the particles do it and exactly when it will happen,« says Søren Fournais.

The funding has been awarded via the highly prestigious ERC Advanced grants, which are awarded to excellent researchers at the top level, and the funds are used to build up a team around a ground-breaking research idea.

Where have I heard about this person before?

Søren Fournais got an ERC Starting Grant from the European Research Council in 2008 for the project Mathematical problems in Superconductivity and Bose-Einstein Condensation, and the Independent Research Fund Denmark awarded him a Sapere Aude DFF-Advanced scholarship in the years 2015-2020.

Søren Fournais’ research into Bose-Einstein-condensates has led to some of the world’s biggest breakthroughs in the field. He has formulated the proof, for example, of an equation for the basic energy state of a Bose-Einstein-condensate that had been left unproven since approximately 1960.

In 2018, the Ministry of Science awarded him the prestigious Eliteforsk award.

What should I do now?

You can read more about the Department of Mathematical Sciences here.

Apart from that, like Søren Fournais, you will have to be patient:

»I think that it’s unrealistic to solve this assignment in five years, but I hope that the project will bring us closer to it than we are today,« says Søren Fournais. »And we still have a lot of sub-targets that we hope to achieve along the way«.